Thanks to @NutzAboutBolts , I've successfully cleaned up my EGR module. Thank you man, you rock! I've noticed an improvement of mileage at moderate speeds. Is this common or is this just wishful thinking on my part? If so, why? I don't understand why recirculating burned gasses into the combustion chamber and reburning it improves MPG.
How many miles on your Prius? How clogged was the cooler? I swapped out our EGR cooler about 50 k miles ago and the mpg increased slightly . But I also slowed down a bit which helps mpg more. Cleaning the cooler goes further with reducing other failures than the mog improvement. Hope that helps .
I just broke 150k miles and I've always driven like a grandma haha What's the collet you're referring to?
The egr cooler is just upstream of the egr valve. If you haven’t cleaned that at 150 k miles, that will need to be addressed.
Is the cooler where the radiator lines go into? I cleaned that as well as the valve. Are we talking about the same thing, the block with fins inside?
EGR does a few things for the engine. It lowers combustion temperatures thus improving the knock limit and allows advanced timing. Heating more air with the same amount of fuel improves the work done on the piston. Toyota says it allows for faster ignition (see "tumble ratio") which means more efficient combustion. And lastly, EGR lowers throttle losses at part throttle - this is what you're noticing. Toyota Global Site | Engine (Atkinson-cycle)[HV] Toyota's Next-Gen Prius to Possess Engine with 40% Thermal Efficiency - World Industrial Reporter Pixel XL ?
Another word for "throttle loss" is "pumping loss": Optimizing fuel economy with EGR | PriusChat Pixel XL ?